1. The sturgeon was common over 200 years ago in large UK rivers including the Severn, Avon, Ouse, some Scottish rivers and the Thames, with remnants of sturgeon found in the medieval remains of Westminster Abbey.

2. Fossilised sturgeons have been found in deposits dating over 54 million years old. They possess many primitive features, including a heterocercal tail (the spine continuing along the upper lobe), a cartilaginous skeleton, and a spiral valve in the lower intestine.

3. The head is covered with hard bony plates that meet to form visible seams.

4. In September 2013, two boys caught a sturgeon near Pembroke Dock. Steve Colclough, of the Institute of Fisheries Management said, “Where it came from is at present a mystery.” Two months later, the Daily Express reported a Siberian sturgeon caught in the Thames. Steve Colclough explained the fish could possibly be one lost from cages in the Gironde River in France some years ago during a caviar farming experiment. But, he said:“We think it is more likely to be an escapee from the UK pet trade. These exotic species are imported and this may show that some are now escaping into the wild.”